Carburetor



Jan. 20, 1931. J. R. FRIANCIS I 18 3 CARBURETOR Filed Deb. 19, 1921 tic I Patented Jan. 20,1931 7 '4 '7 S AT S.

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.iAcoB nrcnennrnancrs, or FLINT, MICHIGAN;

Application filed December 194 1921; SeriaiiIiT o. 52 3:3281

This invention relates to certain new and useful improvements in carburetors and more particularly'to means for retarding the opening movement of the suction controlled air 3 ,6 valve, such as used in connection with Marvel carburetors and is an improvement on the construction of carburetor shown in my application filed June 15, 1921, Serial No. 477,768, the object being to provide an air screw dash pot, by means of which the movementof the air valve will be slightly retarded '1 in opening so as to increase the 'efficie'ncyof the internal combustion engine when the caris known as a quick pick-up; Another and further object of my invention isto provide a carburetor in which the air valve is retarded by a combined fluid and spring dash pot whereby a fine adjustment buretor is installed thereon by obtaining what 2v can be obtained and the movementof the air valve controlled to a nicety so as to obtain the desired results. I

A still further object of the invention is to provide a construction which is capable of being used in connection with'various forms of carburetors where a movable. air valve is employed.

Another object of the invention is to provide'a carburetor having a pivoted air valve to which is connected a pivoted rod which in turn is connected to a piston mounted in a:

hollowrscrew, said piston having a ventin order'to form a dash pot whereby the movement of the valve is retarded.

Other and further objects and advantages of the invention will be hereinafter set forth and the novel features thereof defined by the appended claims. p In the drawing I have shown a side elevation of an ordinary Marvel carburetor, partly in section, comprising a shell 1 having a mixing chamber 2, air inlet 3, high speed nozzle 4, and insert 5 provided with a low speed nozzle as now generally used in this construc- T tion of carburetor. Pivotally mounted on the insert 5 is an air or suction controlled valve 6 which extends up above the high speednozzle 4 and is adapted to be normallyheld against the wall of the mixing chamber. I The above description is given so that the b-pera o pmy i p o oi t i o i f air screw and dash pot can be clearly' underfstoodwhen applied to this type of carburetor,

butit' 'is, oi course;understoodthatfI'donot wish to'liinit myself to the use. or any'par- 55.

ticular type of carburetor 'asjmy' fimproyed constrnction of air screw an'd':"dash pot is capable of being used on various'construc tions ofcarburetorswhere a movable-air valve is employedu fl i f' Q j ,Themixing chamber is ;provide di'with a threaded bore 7 in the wall thereof, in which works the threaded portion .8 "of, tubular adjusting screw 9 which is provided'with a fluted outer end 10 against whicharatchet i 7 spring 11 bears for holdingfthe adjusting I screw in -its' adjusted position-{withinthe threaded bore. H H Slidably mounted within thetubular ad justingffscrew Elis a piston "I i the head of 79 which is apertured at .1 3,.sai1d 'piston sliding 'ireely within the tubular adju'sting'fsOreW and .is normally held in extended position bya springil i so that: the inward movement of the lpistonfwithin "the tubular adjusting screw is resisted by the tension'of the spring and as the piston moves within the tubular screw the air within the? same is I OI,C6d

through thevent or passage 13 which forms a dash pot arrangementsoas toresist the move- 80 ment of the piston withinthe tubular'screw,

Pivotally mounted in theo iter end ofthe I mixing chamber extends within the cylinder formed by the tubular valve sothat'- a certain amount of fuel such as gasoline is drawn within the shell so as to keep the spring thoroughly lubricated.v .I' I Inmy former'application the rod was con? nected; to. the spring so that/thee opening 199 piston and I ovement of the air valve was resisted by the spring alone while in this application,

the piston and bore of the tubular plug forms a fluid dash pot by means of 'which the movementof the piston is retarded so that the opening movement of the air ,ValVe is retarded and by the particular manner of connecting the rod to the piston and air valve a connection is' formed which allows the piston to move freely within the tubular adjusting screw; 1 l

From the foregoing description it will be seen that I have provided an improved con- 'struction of air screw and dash pot for a suction controlled valve used in connection with a;carbur.etor whereby I am ableto. con,-

' trol .thejm'ovementof the'air. valve inlsuch a mannerfthat the valve isslightlyretarded in its opening movement so,,,as to increase the efiiciencyof the internal combustion en gine to which the carburetor'is attached I ca and by the particularconstruction the parts move freely without any danger of the air valve not working properly under vall conditions. By the particular construction ofpiston andscrew, a fluid dash pot isformed wherein the fluid within the tubular screw is displaced by the piston as the suction con; trolled valve is moved into open position and by'varying thesize of the vent or passage, the speed of movement of the piston can bedetermined so that the proper resistance will be obtained to retard thelmove 'ment of thevalve;

' By providing a combination spring-and fluid dash pot for the air valve of thecarburetor, the cylinder of the dash pot is adjustably mounted in respectto the piston whereby. the cubic contents of thecylinder can be'varied and at thesame time the ten:

sion of the springcan be'increased. or deifis'aess v said piston and aspring-disposed in said screw beyond said piston. V v

:;Intestimonyiwhereof I hereunto aflix my signature. 1 JACOB RICHARD FRANCIS.

creased so as to control the movement of the air valve to a nicety.

What I claim is 1. A carbur-etorhaving a mixing chamber 7 provided with high and low speed nozzles, a pivoted suction controlled valve mounted in said mixing chamber over said high speed nozzle, said valve having a bifurcated 1'stem on the upper face thereof; the wall of said mixing chamber being provided with a threaded bore, a tubularscrew working in said bore, .a piston slidably mounted: in said'tubular'screw having an 'opening iiorm? 'ing a passage, for fluid on the movement of said pistoma spring disposed in saidl screw beyond said piston and a rod pivotally ,mounted in said bifurcated stem extending across said mixing chamber abovesaidvalve v and having a pivotalconn-ection with said piston. 7 h 7 2;. A carburetor having a mixing chamber provided with a high and'low speed nozzle, i

a pivotedsuction controlled' valve mounted i in said mixing chamberover said high speed 

